Ive been using mine in an ice fishing hut regularly in similar temps and I can be in a tshirt and shorts. As long as you dont use the thermostat feature on the diesel heater that makes the glow plug turn on and off it should last alot longer. A 100ah lithium battery will last me 7 days running about 7-8hrs a night during 3rd rifle. Im in a 9x12 kodiak cabin tent.
It certainly wont dry as quickly as wood but if you put a hanging rack of some sort in front of the blower your clothes and boots will be dry by morning if running all night. Just my experience using it for the last 1.5 years.
You can get really good 100ah lithium batteries on sale
https://www.litime.com/pages/new-year-sales that have bluetooth so you can keep track of how much battery you are using.
You may need to look into a solar panel and inverter if you are really using the juice.
At the end of the day youll have to weigh out the trade offs of each.
I will say its nice when you can just use the remote to turn on your heater in the AM before you get up and dressed for nights you dont need to run it all the time.